diff --git a/pkgs/development/python-modules/sniffio/default.nix b/pkgs/development/python-modules/sniffio/default.nix
new file mode 100644
index 00000000000..9893bc5828a
--- /dev/null
+++ b/pkgs/development/python-modules/sniffio/default.nix
@@ -0,0 +1,30 @@
+{ buildPythonPackage, lib, fetchPypi, glibcLocales, isPy3k, contextvars
+, pythonOlder
+}:
+
+buildPythonPackage rec {
+  pname = "sniffio";
+  version = "1.0.0";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "1dzb0nx3m1hpjgsv6s6w5ac2jcmywcz6gqnfkw8rwz1vkr1836rf";
+  };
+
+  # breaks with the following error:
+  # > TypeError: 'encoding' is an invalid keyword argument for this function
+  disabled = !isPy3k;
+
+  buildInputs = [ glibcLocales ];
+
+  propagatedBuildInputs = lib.optionals (pythonOlder "3.7") [ contextvars ];
+
+  # no tests distributed with PyPI
+  doCheck = false;
+
+  meta = with lib; {
+    homepage = https://github.com/python-trio/sniffio;
+    license = licenses.asl20;
+    description = "Sniff out which async library your code is running under";
+  };
+}
diff --git a/pkgs/development/python-modules/trio/default.nix b/pkgs/development/python-modules/trio/default.nix
index 4924fa527c6..89addb377dc 100644
--- a/pkgs/development/python-modules/trio/default.nix
+++ b/pkgs/development/python-modules/trio/default.nix
@@ -8,6 +8,7 @@
 , pytest
 , pyopenssl
 , trustme
+, sniffio
 }:
 
 buildPythonPackage rec {
@@ -31,6 +32,7 @@ buildPythonPackage rec {
     async_generator
     idna
     outcome
+    sniffio
   ] ++ lib.optionals (pythonOlder "3.7") [ contextvars ];
 
   meta = {
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 09169463393..2eae6212cd4 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -574,6 +574,8 @@ in {
 
   trio = callPackage ../development/python-modules/trio {};
 
+  sniffio = callPackage ../development/python-modules/sniffio { };
+
   tokenserver = callPackage ../development/python-modules/tokenserver {};
 
   toml = callPackage ../development/python-modules/toml { };